Actuators are used in myriad devices and systems. For example, many vehicles including, for example, aircraft, spacecraft, watercraft, and numerous other terrestrial and non-terrestrial vehicles, include one or more actuators to effect the movement of various control surfaces or components. In many applications such as, for example, in seagoing vehicles, the actuators that are used may be subject to corrosive fluid, such as seawater. Moreover, depending on the type of seagoing vehicle, the actuators that are used may be subject to relatively high pressure. For example, underwater vehicles, including both manned and autonomous (i.e., unmanned) underwater vehicles, include actuators that may be at least partially exposed to the corrosive seawater environment at relatively high pressures.
To prevent or at least inhibit the potentially deleterious effects of seawater corrosion, actuators may be constructed, at least partially, of various corrosion resistant materials. These materials, however, can be relatively expensive, and thus can increase actuator costs and, concomitantly, overall system and/or vehicle costs. Moreover, the use of corrosion resistant materials for gears and bearings can decrease load capacity and/or component life, as compared to the use of non-corrosion-resistant materials. Although various seals and seal systems exist for inhibiting the ingress of fluids, such as seawater, into devices, such as actuators, many of these seals and seal systems are not useful at relatively high pressures. Additionally, seal leakage may increase over time.
Hence, there is a need for a system that at least inhibits the deleterious effects of corrosive fluids on an actuator that does not rely on one or more relatively expensive materials and/or is capable of operation and relatively high pressures for relatively long periods of exposure to a corrosive fluid, such as seawater. The present invention addresses at least these needs.